1. Field of the Invention
The present invention relates to an antenna for inter-chip wireless power transmission, and more particularly, to an antenna for inter-chip wireless power transmission in a 3D-wireless chip package.
2. Description of the Related Art
Recently, technologies of stacking a plurality of chips to reduce the design areas of integrated circuits have been studied. A TSV (Through Silicon Via) technology generally used in recent years in the technologies provides a signal path between stacked chips by forming a vertical electrode through silicon that is a material of semiconductor substrates.
According to the TSV technology, pads for electric connection of stacked chips are not exposed to the outside and the pads are connected to each other between the chips through a via and a bump, so bonding wires can be removed and metal wires patterned on a PCB (Printed Circuit Board) can be removed. Therefore, the TSV technology has the advantage that it is possible to remove parasitic components due to the bonding wires and the PCB metal wires and to achieve inter-chip high-speed communication.
However, since the via is formed by forming a physical hole in a chip and filing the hole with a metallic material, there is a problem in that the development and commercialization costs increase due to the additional semiconductor process. Further, it takes much effort to increase the yield ratio of the via due to a problem like cracks. As a result, the TSV technology increases the manufacturing cost.
In order to solve those problems, recently, an inter-chip wireless communication technology has been studied. Since the inter-chip wireless communication technology performs communication between chips by wireless, it has the advantage that there is no need for making a via through a chip, as in the TSV technology.
FIG. 1 is a view illustrating the concept of an inter-chip wireless communication technology according to the related art. Referring to FIG. 1, the stacked chips each have an antenna for wireless power transmission between them. FIG. 1 is an example in which the antennas of the chips are inductors that induce inductive coupling.
The antenna of the uppermost chip or the lowermost chip can transmit power to the antennas of the other chips by wireless. According to the vertical stacking structure of chips, the distances from transmitting antennas to the receiving antennas are different. Accordingly, there is a problem in that the transmission efficiency is different in accordance with the distance from the transmitting antenna on each layer.
The background of the present invention has been disclosed in Korean Patent Application Publication No. 2012-0040779 (2012.04.30)